Device for fixing the outer end of a hairspring to the cock of timepieces



March 18, 1952 F. MARTI 2,589,717

DEVICE FOR FIXING THE OUTER END OF A HAIRSPRING coc cEs TO E K O IMEPIE ed Feb. 1947 Llllllllll IIIIIIITI INVEN H W772 Ma l ATTQHNE) Patented Mar. 18, 1952 2,589,717 DEVICE FOR FIXING THE OUTER END OF A HAIRSPRING TO T PIECES HE COCK OF TIME- Fritz Marti, La Chaux-de-Fonds, Switzerland Application February 14, 1947, Serial No.

In Switzerland October 30, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires October 30, 1965 1 Claim. 1

In the time-pieces hitherto known, the outer end of the hair-spring is fixed to the cock by a stud. In order to modify the active length of the hair-spring a regulator curb is used, between the pins of which the hair-spring is held freely or gripped resiliently, and these pins are displaced by turning the regulator curb along the outer turn of the hair-spring. The curb has however the disadvantages of diminishing the regulating properties of the regulating device by impairing its isochronism.

An important feature of the present invention resides in that the fixing device comprises two members that grip between them the end of the hair-spring, at least one of these members being so mounted that it can be manipulated, and that when so manipulated it will enable the hairspring to be carried along so as to modify its active length.

One embodiment of the invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a plan View; and

Figure 2 is a section on the line II-II in Figure 1.

In these drawings, i denotes the cock-plate of a time-piece regulated by a balance-wheel, 2 is an index centre-piece fixed to the cock by two screws 3, and bearing at its centre the cover-plate 4 of the upper bearing of the regulator balance-staff, the pierced stone 5 of which is inserted in an aperture in the cock. 6 denotes a Breguet hairspring, the outer end of which is to be fixed to the cock. On the serge of the index centre-piece 2 is mounted with oiled friction a regulator curb I, provided with 3, lug 8. In a thickened flange 8' of this lug is formed a radial slot-guide 9, leading to a circular milling It. In an axial aperture in the bottom of this milling It is pivotally mounted a roller II which is rigid with a toothed pinion I2 and with a star wheel I 3. The lower end of the roller I I is provided with a collet I 4 in which is formed a peripheral groove I5. In the radial slot-guide 9 is mounted a second roller I6, which is rigid with atoothed pinion II, meshing with the pinion I2 of the first roller. The lower end of the roller I6 is provided with a collet I8, the breadth of which corresponds to that of the groove I5 of the roller I I. An approximately S-shaped spring I9, lodged in a peto urge the roller 2 ripheral groove =20 in the regulator curb, tends I 5 towards the roller II, and to keep the pinions I2 and I! of these two rollers in mesh with one another. The outergend of the hair-spring 6 is resiliently nipped between the collet I8 of the roller I6 and the bottom of the groove I5 in the roller II. The spring I9 is kept stressed by a pin 2 I.

In order to regulate the active length of the hair-spring, the outer end of which is resiliently but firmly held by the two rollers II and I5, which take the place of the usual stud, all that is necessary is to turn the manipulating star wheel I3 in the desired direction. In this way a movement of rotation is impressed upon the two rollers, which displace the outer turn of the hairspring, and shorten or lengthen it according to the direction of rotation. A graduated scale is arranged around the milling It in which the manipulating star wheel I3 is lodged. Regulation is therefore efiected not as hitherto by displacing the regulating curb relatively to the stud, but by moving the outer turn of the hair-spring by means of the rollers I I and I 6, which take the place of the stud and curb pins usually employed, the curb 1 remaining stationary.

When assembling or repairing the movement, a preliminary regulation may be efiected by slightly modifying the initial angular position of the regulator curb, which position may be selected according to the configuration of the calibre, and above all the shape of the cock, in whatever way is the most practical for the manipulation of the star wheel.

The two fixing rollers might be mounted directly upon the cock, or upon a fixed piece attached to the cock. One of them might be fixed and the other rotatable. One of the rollers might be replaced by a pin.

What I claim is:

In a device for fixing the outer end of a hair spring to the cock of a time-piece, comprising a support member having a recess, two rollers provided with meshing gears and having cooperating surfaces adapted to nip the end of the hair spring therebetween, said rollers being rotatably mounted in said support with their gears on one side of the support and the said cooperating surfaces on the opposite side of said support, one of said rollers being disposed in a radial slot in said support member and being slidable in said slot relative to the other roller, manually operable means for rotating said rollers whereby to shift the hair spring and to modify the active length thereof, and a spring disposed in said recess in said support urging said second-named roller against said first-named roller, said spring engaging said second-named roller substantially in the center of the distance between the gears and the nipping surfaces, whereby the pressure 10 of said spring is substantially equally distributed on the gears and on the nipping surfaces.

FRITZ MARTI.

REFERENCES CITED UNITEl STATES PATENTS Number Name Date 311,609 Reed Feb. 3, 1885 670,364 Bolton Mar. 19, 1901 FOREIGN PATENTS Number Country Date 50,092 Switzerland Jan. 6, 1910 52,751 Switzerland Oct. 31, 1910 Switzerland July 16, 1948 

